Subsea Electric Submersible Pump Module System And Method

ABSTRACT

The present disclosure provides a simplified electric submersible pump (ESP) system for installation into a borehole, regardless of whether a caisson is formed in the borehole or whether an internal volume under a cap of a housing with the ESP is pressurized. A frame with associated ESP equipment can be mounted over the borehole. The ESP system can allow direct access to the ESP without having to lift the frame or a housing surrounding the ESP for maintenance and repair. A bypass provides flow during the period in which the ESP in non-operational.

CROSS REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The disclosure generally relates to the production of hydrocarbons fromsubsea formations. More particularly, the disclosure relates to a subseapumping system and method generally located on the seafloor.

2. Description of the Related Art

In producing hydrocarbons from subsea formations, a number of wells aretypically drilled into the seafloor. A subsea pump is often necessary toprovide additional pressure or lifting head to lift well productionfluids from the well to the water or land surface for processing intothe desired hydrocarbons. Historically, the pumps have been electricsubmersible pumps (ESPs) that are installed in a borehole with a caissonof steel or concrete lining. The ESPs have an electrical motor connectedto a rotary pump and associated equipment, such as seal sections forequalizing hydrostatic fluid pressure, a pump intake section, andelectrical and fluid connectors. The ESP intake receives the wellproduction fluids and the ESP discharge is connected to a riser, pipe,or other conduit for providing the fluids to the surface. The caissoncan be sealed so that the fluids are received into the caisson first,and then allowed to flow into the ESP intake. The sealed caisson mayalso provide for a release of gas components entrapped in the wellproduction fluids prior to the ESP, so that the ESP is able to pump moreliquid components.

ESPs require periodic maintenance and have to be disconnected andtypically brought to the surface. The scheduled maintenance may needseveral months' lead time. Also, ESPs can malfunction and causeunplanned maintenance or replacement. In each case, the production fromthe well is reduced or stopped during this period and the motivation inthe field is to reduce the downtime.

For example, US Publication No. 2011/0056699 provides for multiple ESPsinstalled as a module in a parallel flow path to discharge to a commonmanifold. The ESP module is installed in a sealed caisson with the wellproduction flowing into the caisson and then into one or more of the ESPintakes. Each ESP can be selectively operated to provide an overalldesired flow rate and lifting head. While this design provides backupcapabilities if one ESP fails, the design still suffers from the need toshut down production from the well to open the sealed caisson and pullthe ESP module for maintenance and repair.

As another example, U.S. Pat. No. 7,516,795 shows an almost horizontalpumping module installed above the seafloor. A stationary flow base isinstalled on the seafloor and connected with the well productionhydrocarbons. A pumping module can be releasably connected with the flowbase. The entire pumping module can be disconnected and pulled to thesurface when maintenance and repairs are needed. The design allows fordisconnection and replacement with a backup unit, while the originalunit is non-operational. However, the weight of the entire pumpingmodule may require lifting equipment that common service vessels may nothave. The weight and size may require special rigging with added expenseand additional lead times for scheduling.

US Publication No. 2010/0119382 also shows a horizontal installation ofa pumping unit on a skid that can be lowered to the seafloor andinstalled on top of the seafloor. The pumping unit includes a horizontalouter housing which encloses an ESP system. Well production fluids enterthe housing, encircled the pumping unit in the housing, flow into thepump intake, and then are pressurized through the pump discharge. Theentire pumping unit with the housing and ESP system can be disconnectedat a connector on each of the inlet and outlet of the housing. A bypasscan be used while the pumping unit is non-operational. Depending on theweight and size of the pumping unit with the housing in addition to theESP system, special rigging may be required.

U.S. Pat. No. 7,150,325 shows an ESP system in a primary housinginstalled in the seafloor. The primary housing communicates with anintake conduit for receiving well production fluids from an adjacentwell. A capsule hanger is installed in the primary housing and extendsdownward to form a receptacle. A capsule lands on the capsule hanger andsealingly engages the primary housing intake and sealingly engages thedownward receptacle. An ESP is mounted inside the capsule and has anintake open to an inner volume of the capsule. Well productions fluidsenter through the primary housing intake, flow around the capsule hangerand the receptacle, into an inner volume of the capsule, into the ESPintake, and out through the capsule through an outlet in the head. Formaintenance and repair, the well productions fluids are stopped, a capon the primary housing is removed, and the capsule with the ESP thereincan be retrieved. Thus, the retrieval of a combined housing with an ESPtherein is similar to the combined housing with an ESP in the above USis Publication No. 2010/0119382.

Despite these designs, there remains then a need to simplify thestructure of an ESP subsea installation that can allow ease of access,minimal time to schedule maintenance, and minimal downtime ofproduction.

BRIEF SUMMARY OF THE INVENTION

The present disclosure provides a simplified electric submersible pump(ESP) system for installation into a borehole, regardless of whether acaisson is formed in the borehole or whether an internal volume under acap of a housing with the ESP is pressurized. A frame with associatedESP equipment can be mounted over the borehole. The ESP system can allowdirect access to the ESP without having to lift the frame or a housingsurrounding the ESP for maintenance and repair. A bypass provides flowduring the period in which the ESP in non-operational.

The disclosure provides a system for pumping fluids from a subsealocation, comprising: an inlet conduit; a bypass valve coupled to theinlet conduit; a bypass conduit coupled to the bypass valve; an electricsubmersible pump (ESP) flow circuit coupled to the bypass conduit; andan outlet conduit coupled to the receiver outlet of the ESP flow circuitand to the bypass conduit. The ESP flow circuit coupled to the bypassconduit, comprises an ESP valve; a vertically disposed ESP conduit loopcoupled to the ESP valve and configured to fit into a vertical boreholeformed in a seafloor; an ESP housing coupled to the ESP conduit loop,comprising an ESP receiver having a receiver outlet and a removable cap;a vertically disposed ESP hanger coupled in an interior volume of theESP receiver and supported by the ESP receiver, the ESP hanger having aninternal bore fluidicly coupled to the receiver outlet; and a verticallydisposed ESP coupled to the ESP hanger, the ESP having an inlet withinthe ESP conduit loop and an outlet coupled to the internal bore of theESP hanger; wherein flow through the ESP conduit loop and the ESPhousing is independent of any flow in the borehole formed in theseafloor, and wherein the receiver is configured to allow removal of theESP hanger with an exposed ESP independent of a removal of the ESPreceiver and to allow direct access to the ESP.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an elevational front schematic view of an exemplary system forpumping fluids from a subsea location according to the presentinvention.

FIG. 2 is a side schematic view of the embodiment of FIG. 1.

FIG. 3 is a top schematic view of the embodiment of FIG. 1.

FIG. 4 is a schematic cross sectional view of an ESP housing containingan ESP.

FIG. 5 is a schematic cross section view of an electrical through theESP housing.

DETAILED DESCRIPTION

The Figures described above and the written description of specificstructures and functions below are not presented to limit the scope ofwhat Applicant has invented or the scope of the appended claims. Rather,the Figures and written description are provided to teach any personskilled in the art to make and use the inventions for which patentprotection is sought. Those skilled in the art will appreciate that notall features of a commercial embodiment of the inventions are describedor shown for the sake of clarity and understanding. Persons of skill inthis art will also appreciate that the development of an actualcommercial embodiment incorporating aspects of the present disclosurewill require numerous implementation-specific decisions to achieve thedeveloper's ultimate goal for the commercial embodiment. Suchimplementation-specific decisions may include, and likely are notlimited to, compliance with system-related, business-related,government-related and other constraints, which may vary by specificimplementation, location and from time to time. While a developer'sefforts might be complex and time-consuming in an absolute sense, suchefforts would be, nevertheless, a routine undertaking for those ofordinary skill in this art having benefit of this disclosure. It must beunderstood that the inventions disclosed and taught herein aresusceptible to numerous and various modifications and alternative forms.The use of a singular term, such as, but not limited to, “a,” is notintended as limiting of the number of items. Also, the use of relationalterms, such as, but not limited to, “top,” “bottom,” “left,” “right,”“upper,” “lower,” “down,” “up,” “side,” and the like are used in thewritten description for clarity in specific reference to the Figures andare not intended to limit the scope of the invention or the appendedclaims. Where appropriate, one or more elements may have been labeledwith an “A” or “B” to designate various members of a given class of anelement. When referring generally to such elements, the number withoutthe letter is used. Further, such designations do not limit the numberof members that can be used for that function.

The present disclosure provides a simplified electric submersible pump(ESP) system for installation into a borehole, regardless of whether acaisson is formed in the borehole or whether an internal volume under acap of a housing with the ESP is pressurized. A frame with associatedESP equipment can be mounted over the borehole. The ESP system can allowdirect access to the ESP without having to lift the frame or a housingsurrounding the ESP for maintenance and repair. A bypass provides flowduring the period in which the ESP in non-operational.

FIG. 1 is an elevational front schematic view of an exemplary system forpumping fluids from a subsea location according to the presentinvention. FIG. 2 is a side schematic view of the embodiment of FIG. 1.FIG. 3 is a top schematic view of the embodiment of FIG. 1. FIG. 4 is aschematic cross sectional view of an ESP housing containing an ESP.

FIG. 5 is a schematic cross section view of an electrical through theESP housing. The Figures will be described in conjunction with eachother. The exemplary system 2 for pumping fluids from a subsea locationincludes an assembly of pipe, tubing, and other conduits and variousequipment mounted on a frame 10. A portion of the system is disposeddownward into a borehole 4 formed in a seafloor 3. The boreholeoptionally can be cased with a caisson 6, but the operation of the ESPsystem is independent of a caisson or a pressurized volume in thecaisson. The frame 10 can be mounted on a support structure 8 that ismounted to the caisson 6.

Starting on the left of FIG. 1, an inlet 16 can be fluidicly coupled toone or more wells (not shown) from which well production fluids flowinto the inlet. The inlet 16 can be supported by an inlet support 12 ofvarious structural members. The inlet 16 can be coupled to an inletconduit 18 forming an inlet flow circuit that can be divided into abypass flow circuit 22 and an ESP flow circuit 32. The bypass circuit 22includes conduits, clamps, valves and other equipment, including abypass valve 23 disposed therein to control flow through the bypass flowcircuit. The bypass circuit 23 can rejoin the ESP flow circuit 32 on adownstream portion of the bypass flow circuit and ESP flow circuit afterthe ESP 52 described below. After the bypass circuit 22 rejoins the ESPflow circuit 32 and is coupled with an outlet conduit 26, the outletconduit can form an outlet flow circuit and be coupled to an outlet 30of the system 2. The outlet 30 and associated conduit 26 can besupported by an outlet support 28 of various structural members. Theoutlet 30 can be coupled up to a riser, piping, or other conduit (notshown) that can be used to flow the well production fluids to thesurface for further processing.

The ESP flow circuit 32 includes at least one valve 20 that can isolatethe ESP flow is circuit 32 from flow through the bypass circuit 22. Thevalve 20 can be disposed in close proximity to the bypass flow circuit22. The valve 20 can be coupled to an ESP inlet conduit 34 that can joinan ESP conduit loop 38. In some embodiments, an additional valve 36 canbe coupled to the ESP inlet conduit as an additional valve to controlthe fluid therethrough. The conduit loop 38 is generally shaped into aloop that can extend downward into the borehole 4. If a caisson 6 isinstalled in the borehole, then the loop can extend downward into thecaisson as well. The length of the loop can vary and, as an example butwithout limitation, could be about 30 meters to 40 meters long. The loopcan form a U-turn and come back up toward the assembly of valves andconduits on the frame 10. At least one of the downwardly disposedconduits of the ESP conduit loop can have a sufficient inside diameterand length into which the ESP 52 can be inserted vertically.

An ESP housing 40 can form a portion of the ESP conduit loop 38. The ESPhousing 40 includes an ESP receiver 42 that receives an assembly towhich the ESP 52 is coupled, as explained below. The ESP receiver 42generally includes a cap 44 to restrict debris and the like fromentering an internal volume 43 of the receiver. The design of the system2 does not depend upon the pressurized internal volume 53 in contrast toearlier designs. Thus, the cap 44 can be opened without requiring timefor depressurization of an internal volume of earlier pressurizeddesigns. The ESP receiver 42 includes a receiver outlet 46 through whichproduction fluids from the discharge of the ESP 52 can be pumped. TheESP receiver 42 also includes a hanger shoulder 48, which can be atapered surface extending inwardly toward the internal volume 43 of theESP receiver 42. An ESP hanger 50 is coupled with the ESP 52 in someembodiments through an intermediate conduit 54. The ESP hanger 50includes a bore 56 therethrough that is fluidicly coupled to the conduit54 and the discharge of the ESP 52 on a first portion. On a secondportion of the ESP hanger 50 that is distal from the first portion, ahanger outlet 60 intersects the bore 56 and is fluidicly coupled withthe receiver outlet 46. Thus, the well production fluid enters into anintake of the ESP 52, and is discharged through the conduit 54, throughthe bore 56, laterally outward through the hanger outlet 60, through thereceiver outlet 46, and thence on to other portions of the ESP flowcircuit 32. The ESP hanger 50 can sealingly engage the internal surfacesof the ESP receiver 42 through seals 62 and 64. Thus, the sealinglyengaged ESP hanger 50 restricts pressure of the well production fluidsbelow the hanger from entering the internal volume 43 above the hanger,so that the cap 44 is not under a pressurized embodiment from internalpressure.

Electrical service to the ESP 52 can be supplied through an electricalcable 74 from the is ESP 52 through the ESP hanger 50 and laterallyoutward through the ESP receiver 42. An electrical connector 76 can becoupled to the electrical cable 74. The electrical connector 76 can beused to detachably couple electrical service to the electrical cable 74,so that the ESP hanger 50 can be removed from the ESP receiver 42.

Once the well production fluids have been pumped through the ESP 52 anddischarged through the ESP receiver 42, the fluid can reenter theconduit of the ESP flow circuit 32 external to the ESP housing 40. Avalve 66 coupled in the ESP flow circuit 32 can be used to control theflow on the ESP flow circuit downstream from the ESP housing 40. Thevalve 66 can further be coupled to an ESP outlet conduit 72, which canbe coupled to another valve 24. The ESP flow circuit 32 can rejoin thebypass flow circuit 22 and well production fluids can then flow into theoutlet conduit 26 that is described above.

The design and circuitry of the flow paths can vary. In someembodiments, a bypass circuit may not be used. In other embodiments, theextra set of valves on the inlet and outlet to the ESP conduit loop 38may not be used. In some embodiments, a caisson may be used and in otherembodiments, an open frame structure can be used to protect the ESPconduit loop. In some embodiments, the frame 10 can be mounted to theseafloor. Other and further embodiments utilizing one or more aspects ofthe inventions described above can be devised without departing from thespirit of the disclosed invention.

Further, the various methods and embodiments of the system can beincluded in combination with each other to produce variations of thedisclosed methods and embodiments. Discussion of singular elements caninclude plural elements and vice-versa. References to at least one itemfollowed by a reference to the item may include one or more items. Also,various aspects of the embodiments could be used in conjunction witheach other to accomplish the understood goals of the disclosure. Unlessthe context requires otherwise, the word “comprise” or variations suchas “comprises” or “comprising,” should be understood to imply theinclusion of at least the stated element or step or group of elements orsteps or equivalents thereof, and not the exclusion of a greaternumerical quantity or any other element or step or group of elements orsteps or equivalents thereof. The device or system may be used in anumber of directions and orientations. The term “coupled,” “coupling,”“coupler,” and like terms are used broadly herein and may include anymethod or device for securing, binding, bonding, fastening, attaching,joining, inserting therein, forming thereon or therein, communicating,or otherwise associating, for example, mechanically, magnetically,electrically, is chemically, operably, directly or indirectly withintermediate elements, one or more pieces of members together and mayfurther include without limitation integrally forming one functionalmember with another in a unity fashion. The coupling may occur in anydirection, including rotationally.

The order of steps can occur in a variety of sequences unless otherwisespecifically limited. The various steps described herein can be combinedwith other steps, interlineated with the stated steps, and/or split intomultiple steps. Similarly, elements have been described functionally andcan be embodied as separate components or can be combined intocomponents having multiple functions.

The invention has been described in the context of preferred and otherembodiments and not every embodiment of the invention has beendescribed. Obvious modifications and alterations to the describedembodiments are available to those of ordinary skill in the art. Thedisclosed and undisclosed embodiments are not intended to limit orrestrict the scope or applicability of the invention conceived of by theApplicant, but rather, in conformity with the patent laws, Applicantintends to protect fully all such modifications and improvements thatcome within the scope or range of equivalent of the following claims.

What is claimed is:
 1. A system for pumping fluids from a subsealocation, comprising: an inlet conduit; a bypass valve coupled to theinlet conduit; a bypass conduit coupled to the bypass valve; an electricsubmersible pump (ESP) flow circuit coupled to the bypass conduit,comprising: an ESP valve; a vertically disposed ESP conduit loop coupledto the ESP valve and configured to fit into a vertical borehole formedin a seafloor; an ESP housing coupled to the ESP conduit loop,comprising an ESP receiver having a receiver outlet and a removable cap;a vertically disposed ESP hanger coupled in an interior volume of theESP receiver and supported by the ESP receiver, the ESP hanger having anis internal bore fluidicly coupled to the receiver outlet; and avertically disposed ESP coupled to the ESP hanger, the ESP having aninlet within the ESP conduit loop and an outlet coupled to the internalbore of the ESP hanger; wherein flow through the ESP conduit loop andthe ESP housing is independent of any flow in the borehole formed in theseafloor, and wherein the receiver is configured to allow removal of theESP hanger with an exposed ESP independent of a removal of the ESPreceiver and to allow direct access to the ESP; and an outlet conduitcoupled to the receiver outlet of the ESP flow circuit and to the bypassconduit.
 2. The system of claim 1, wherein a flow of fluids into thepump inlet is independent of flow of other fluids in the borehole. 3.The system of claim 1, wherein flow of the fluids into the ESP intake isexclusive of flow in the borehole.
 4. The system of claim 1, wherein theborehole comprises nonpressurized borehole.
 5. The system of claim 1,wherein the ESP comprises a pump that is oriented inline with flowthrough the ESP conduit loop.
 6. The system of claim 1, furthercomprising a bypass conduit coupled to an inlet of the ESP conduit loopon one portion and an outlet of the ESP conduit loop on a secondportion.
 7. The system of claim 6, further comprising a valve disposedin the bypass conduit and configured to close to restrict flow throughthe bypass conduit.
 8. The system of claim 7, further comprising a valvedisposed in the ESP conduit loop and configured to close to restrictflow through the ESP conduit loop.
 9. The system of claim 1, furthercomprising a detachable electrical connection coupled through thereceiver to the ESP.
 10. The system of claim 1, wherein the ESP receivercomprises a zone above the ESP hanger and wherein the zone isnon-pressurized during flow through the ESP hanger.
 11. The system ofclaim 1, further comprising a caisson at least partially surrounding theESP conduit loop